I have very little to say about this myself, except one question to all the folks out there who keep suggesting we gun nuts are paranoid nuts for suggesting more guns are the problem:
If you were sitting in a school auditorium, you suddenly heard a loud “BANG!” followed by another, then another. You turn around and see a ban walking down the aisle wielding a shotgun, taking aim and shooting at people along the way. Unbeknown to you, the man next to you is a competitive pistol shooter, and has been shooting since he was a child. He immediately grabs you, and pulls you down to cover.  At this point, would you prefer the man next to you be armed, and have the ability to end all this will a well placed shot?  Or would you prefer that the state has made him every bit as helpless as it has made you?
Of course, I know what the answer will be. That if we allow people to carry guns, the man next to me is more likely to be an inbred yahoo who can’t hit the side of the barn, and will just kill more innocents. Because clearly it’s those types of people who own and carry guns. One day perhaps these people will surrender their predjuicial fantasies, but it seems an awful lot of people are willing to see an awful lot of other people cowering in the face of these monsters, rather than allow for the possibility that someone could do something about it.
“rather than allow for the possibility that someone could do something about it.”
You really can’t allow that line of thought. If you accept the fact that “a regular person” at the site could have done something to prevent or lessen the damage, then you might start to think that maybe you could have done something to help. You might even blame yourself for doing nothing.
Much easier to just blame someone else – cops, legislators, the NRA, etc.